High refractive index hydrogel compositions for ophthalmic implants

ABSTRACT

Optically transparent, high refractive index hydrogels and intraocular lenses fabricated therefrom. The preferred hydrogels have a refractive index of 1.45 or above and a water content of approximately 5 to 30 percent by weight.

This application is a divisional application of prior application Ser.No. 09/209,552 filed Dec. 11, 1998 now U.S. Pat. No. 6,329,485.

FIELD OF THE INVENTION

The present invention relates to novel ophthalmic lens materials and amethod for making and using the same. More particularly, the presentinvention relates to soft, optically transparent, high refractive indexhydrogel materials particularly suited for use in the production ofintraocular lenses, and a method for manufacturing and using the same.

BACKGROUND OF THE INVENTION

Since the 1940's optical devices in the form of intraocular lenses(IOLs) have been utilized as replacements for diseased or damagednatural ocular lenses. In most cases, an intraocular lens is implantedwithin an eye at the of surgically removing the diseased or damagednatural lens, such as for example, in the case of cataracts. Fordecades, the preferred material for fabricating such intraocular lenseswas poly(methyl methacrylate), which is a rigid, glassy polymer.

Softer, more flexible IOLs have gained in popularity in recent years dueto their ability to be compressed, folded, rolled or otherwise deformed.Such softer IOLs may be deformed prior to insertion thereof through anincision in the cornea of an eye. Following insertion of the IOL in aneye, the IOL returns to its original pre-deformed shape due to thememory characteristics of the soft material. Softer, more flexible IOLsas just described may be implanted into an eye through an incision thatis much smaller, i.e., less than 4.0 mm, than that necessary for morerigid IOLs, i.e., 5.5 to 8.0 mm. A larger incision is necessary for morerigid IOLs because the lens must be inserted through an incision in thecornea slightly larger than the diameter of the inflexible IOL opticportion. Accordingly, more rigid IOLs have become less popular in themarket since larger incisions have been found to be associated with anincreased incidence of postoperative complications, such as inducedastigmatism.

With recent advances in small-incision cataract surgery, increasedemphasis has been placed on developing soft, foldable materials suitablefor use in artificial IOLs. In general, these materials fall into one ofthree categories: hydrogels, silicones and low glass transitiontemperature acrylics.

In general, high water content hydrogel materials have relatively lowrefractive indexes, making them less desirable than other materials withrespect to minimal incision size. Low refractive index materials requirea thicker IOL optic portion to achieve a given refractive power.Silicone materials may have a higher refractive index than high-watercontent hydrogels, but tend to unfold explosively after being placed inthe eye in a folded position. Explosive unfolding can potentially damagethe corneal endothelium and/or rupture the natural lens capsule andassociated zonules. Low glass transition temperature acrylic materialsare desirable because they typically have a high refractive index andunfold more slowly and more controllably than silicone materials.Unfortunately, low glass transition temperature acrylic materials, whichcontain little or no water initially, may absorb pockets of water invivo causing light reflections or “glistenings”. Furthermore, it isdifficult to achieve ideal folding and unfolding characteristics due tothe temperature sensitivity of the acrylic polymers.

U.S. Pat. No. 5,480,950 issued Jan. 2, 1996 teaches of high refractiveindex hydrogel materials having a hydrated equilibrium water content ofat least 57% for use in the manufacture of IOLs. The high refractiveindex hydrogel materials are crossinked polymers prepared from mixturesof N-vinylpyrrolidone, 4vinylpyrimidine and a vinyl pyridine havingequilibrium water contents up to 90% and refractive indexes of 1.560 to1.594 in the dry state. The IOLs as described are not implanted in ahydrated state. Rather, the IOLs are implanted in a dry, folded andelongated state and hydrated in situ. The refractive indexes in thehydrated state as used in the eye are not provided.

U.S. Pat. No. 5,693,095 issued Dec. 2, 1997 teaches of high refractiveindex, low water content IOL materials. The materials taught in thisparticular patent are acrylic materials having an elongation of at least150%. IOLs manufactured from a material having such elongationcharacteristics will not crack, tear or split when folded. However, suchlow water content acrylic materials have been found to be lessbiocompatible than higher water content hydrogel materials whenmanufactured into and used as IOL devices.

SUMMARY OF THE INVENTION

Soft, foldable hydrogel lens materials having relatively high watercontents and unexpectedly high refractive indexes particularly suitedfor use as intraocular lenses (IOLs), or other ophthalmic devices suchas but not limited to contact lenses, keratoprostheses and corneal ringsor inlays, have now been discovered. The subject hydrogel lens materialscontain only two principal components: a high refractive index monomerthat is usually hydrophobic but not necessarily so, and a hydrophilicmonomer. The hydrogel materials of the present invention are copolymerscomprising at least about 70% by weight of the two principal monomericcomponents whereby the hydrophilic monomer is present in an amountgreater than that of the high refractive index monomer to maximize watercontent. The remainder of the hydrogel material formulation comprises upto approximately 30% water, crosslinkers, initiators, UV absorbers andlike additives.

Accordingly, it is an object of the present invention to provide abiocompatible IOL material having a high refractive index

Another object of the present invention is to provide a hydrogel IOLmaterial having a high refractive index

Another object of the present invention is to provide a hydrogel IOLmaterial that has a high refractive index and is colorless.

Another object of the present invention is to provide a hydrogel IOLmaterial that has a high refractive index and is transparent.

Still another object of the present invention is to provide a hydrogelIOL material that is relatively simple to manufacture.

These and other objectives and advantages of the present invention, someof which are specifically described and others that are not, will becomeapparent from the detailed description and claims that follow.

DETAILED DESCRIPTION OF THE INVENTION

The unique hydrogel materials of the present invention maximize bothrefractive index and water content for use in the manufacture ofophthalmic devices such as intraocular lenses (IOLs). Typical refractiveindexes for acrylic polymers in the absence of water are on the order of1.48 to 1.55, depending on the chemical structures of the monomer orcomonomers comprising the material. Because the refractive index ofwater is low, i.e., 1.33, adding water to an acrylic polymer orcopolymer decreases the refractive index of the hydrated materialrelative to the anhydrous polymer or copolymer. For this reason, theproperties of refractive index and water content are inverselyproportional. In the present invention, refractive index is maximized inthe presence of water, by employing monomers that result in the highestrefractive indexes in the absence of water. Monomers containing arylgroups, sulfur atoms or the halogens, chlorine, bromine and iodine formpolymers having high refractive indexes. To maximize water content andrefractive index in the present materials, a hydrophilic monomer iscombined with a high refractive index comonomer. It is unexpected thatsuch relatively high water content materials may be successfullysynthesized to have high refractive indexes since water generally lowersthe refractive indexes of hydrogels.

The presence of water in the materials of the present invention isdesirable for two reasons, i.e., biocompatibility and flexibility. Thepresence of water usually renders a material more biocompatible than acorresponding material having no water content. Polymers containing somewater are less prone to attach to living tissue. A water content of 25%or higher is most desirable to prevent the attachment and proliferationof lens epithelial cells on the IOL implant surface. Lower water contentmaterials are acceptable for applications, such as phakic IOLs where thematerial will not be exposed to lens epithelial cells. Water also actsas an internal plasticizer, which makes the resulting material easier tofold or deform over a broad range of temperatures.

Materials of the present invention with high refractive indexes are alsodesirable to allow manufacturers to manufacture thinner IOLs. A thin IOLor thin IOL optic is critical in enabling a surgeon to minimize incisionsize. Keeping the surgical incision size to a minimum reducesintraoperative trauma and postoperative complications. A thin IOL isalso critical for accommodating certain anatomical locations in the eyesuch as the anterior chamber and the ciliary sulcus. IOLs may be placedin the anterior chamber for increasing visual acuity in both aphakic andphakic eyes and placed in the ciliary sulcus for increasing visualacuity in phakic eyes.

The preferred hydrogel materials of the present invention have theflexibility required to allow the same to be folded or deformed so thatIOLs made therefrom may be introduced into an eye through the smallestpossible incision. To achieve this flexibility characteristic, the glasstransition temperature (Tg) of the material is likewise of considerableimportance. A glass transition temperature of 20 degrees Celsius or lessmeasured by differential scanning calorimetry at 10 degrees Celsius perminute and determined at the midpoint of the transition of the heat fluxcurve, must be achieved in the subject materials to be acceptable forpurposes of desirable folding of the implant. It was unexpected thatmaterials could be synthesized having the desired refractive index,water content and glass transition temperature because many highrefractive index monomers have bulky side-chains which restrict chainmobility and drastically increase the overall glass transitiontemperature of the copolymer. As a general rule, acrylates producepolymers with lower glass transition temperatures than the correspondingmethacrylates and are therefor preferred. As mentioned above, the watercontent of the subject materials also plays an important role in thefoldability and deformability of the subject material. Polymerflexibility was found to be proportional to water content and polymerglass transition temperature and refractive index were found to beinversely proportional to water content. Therefore, a delicate balancebetween water content, glass transition temperature and refractive indexmust be struck in the synthesis of the subject unique hydrogel materialsto be suitable for use in ophthalmic applications.

The novel hydrogel materials of the present invention are copolymerscomprising only two principal monomeric components: a high refractiveindex monomer and a hydrophilic monomer. The unique characteristics ofthe materials of the present invention are achieved using a largeramount of the hydrophilic monomer than that of the high refractive indexmonomer. Accordingly, it is unexpected that the relatively high watercontent hydrogel materials of the present invention would have the highrefractive indexes achieved since water generally lowers the refractiveindex thereof.

Hydrophilic monomers suitable for use in the manufacture of thematerials of the present invention are represented by Formula I below

wherein R₁ is selected from the group consisting of hydrogen and C₁₋₆alkyl such as for example but not limited to methyl, ethyl, propyl andbutyl but preferably methyl for its common availability, and R₂ isselected from the group consisting of hydrogen, an alkali metal or analkaline earth metal such as for example but not limited to sodium,potassium and magnesium, C₁₋₆ hydroxyalkyl such as for example but notlimited to hydroxyethyl, hydroxypropyl and hydroxybutyl, C₄₋₁₂hydroxyalkoxyalkyl such as for example but not limited tohydroxyethoxyethyl, hydroxybutoxybutyl and hydroxymethoxypropyl, C₄₋₁₂hydroxydialkoxyalkyl such as for example but not limited tohydroxydiethoxyethyl, hydroxydibutoxybutyl and hydroxydiethoxypropyl,C₂₋₁₂ alkoxyalkyl such as for example but not limited to methoxyethyland ethoxybutyl, C₃₋₁₂ polyalkoxyalkyl such as for example but notlimited to methoxyethoxyethyl, methoxyethoxybutyl, andethoxybutoxyethyl, C₃₋₁₅ polyalkoxyhydroxyalkyl such as for example butnot limited to polyethylene glycol, polypropylene glycol andpolybutylene glycol, and C₂₋₁₂ dihydroxyalkyl such as for example butnot limited to glycerol, dihydroxybutyl and dihydroxyhexyl.

Suitable hydrophilic monomers for use in the present invention includefor example but are not limited to 2-hydroxyethyl methacrylate,hydroxyethoxyethyl methacrylate, hydroxydiethoxyethyl methacrylate,methoxyethyl methacrylate, methoxyethoxyethyl methacrylate,methoxydiethoxyethyl methacrylate, poly(ethylene glycol)methacrylate,methoxy-poly(ethylene glycol)methacrylate, methacrylic acid, sodiummethacrylate, glycerol methacrylate, hydroxypropyl methacrylate, andhydroxybutyl methacrylate.

The preferred hydrophilic monomer is 2-hydroxyethyl methacrylate (HEMA)to maximize water content.

High refractive index monomers suitable for use in the manufacture ofthe materials of the present invention are represented by Formulas IIthrough IV below,

wherein R₃ is selected from the group consisting of hydrogen and C₁₋₆alkyl such as for example but not limited to methyl, ethyl and propylbut preferably hydrogen and methyl for common availability, R₄ isselected from the group consisting of C₆₋₂₅ aryl such as for example butnot limited to phenyl and diphenyl, C₆₋₂₅ hydroxyaryl such as forexample but not limited to hydroxyphenyl and hydroxydiphenyl, C₆₋₂₅aryloxyaryl such as for example but not limited to phenoxyphenyl anddiphenoxyphenyl, C₁₂₋₂₅ polyhydroxyaryl such as for example but notlimited to polyhydroxyphenyl and polyhydroxydiphenyl, C₁₂₋₃₅ polyarylsuch as for example but not limited to diphenyl and triphenyl, C₆₋₁₅arylalkyl such as for example but not limited to benzyl, 2-phenylethyland 3-phenylpropyl, C₁₂₋₃₅ polyarylalkyl such as for example but notlimited to diphenylmethyl, diphenylethyl, diphenylpropyl andtriphenylmethyl, C₆₋₁₅ alkoxyaryl such as for example but not limited to4-methoxybenzyl, 4-ethoxybenzyl and 4butoxybenzyl, C₆₋₁₆ aryl halidessuch as for example but not limited to pentabromophenyl,pentachlorophenyl and tribromophenyl, C₆₋₁₅ aryloxyalkyl such as forexample but not limited to 2-phenoxyethyl, 3-phenoxypropyl and4-phenoxybutyl, C₁₋₇ alkyl halides such as for example but not limitedto 2,3-dibromopropyl, 2,3-dichloropropyl and 2,3-dibromobutyl, C₆₋₁₅arylthioalkyl such as for example but not limited to phenylthioethyl,phenylthiopropyl and phenylthiobutyl, C₆₋₁₅ aryloxyalkyl halides such asfor example but not limited to 4-chorophenoxyethyl, 4-bromophenoxyethyland 3,5-dichlorophenoxyethyl and C₆₋₁₅ aryloxyalkoxyalkyl such as forexample but not limited to 2-phenoxyethoxyethyl and2-phenoxyethoxybutyl, and R₅ is selected from the group consisting ofhydrogen, C₁₋₃ alkyl such as for example but not limited to methyl andpropyl, and C₆₋₁₅ alkylaryl such as for example but not limited tomethylphenyl, propylphenyl and butylphenyl.

Suitable high refractive index monomers include for example but are notlimited to phenyl acrylate, phenyl methacrylate, benzyl acrylate, benzylmethacrylate, 2-phenylethyl acrylate, 2-phenylethyl methacrylate,2-phenoxyethyl acrylate, 2-phenoxyethyl methacrylate, phenylthioethylacrylate, phenylthioethyl methacrylate, 2,4,6-tribromophenyl acrylate,2,4,6-tribromophenyl methacrylate, pentabromophenyl acrylate,pentabromophenyl methacrylate, pentachlorophenyl acrylate,pentachlorophenyl methacrylate, 2,3-dibromopropyl acrylate,2,3-dibromopropyl methacrylate, 2-naphthyl acrylate, 2-naphthylmethacrylate, 4-methoxybenzyl acrylate, 4-methoxybenzyl methacrylate,2-benzyloxyethyl acrylate, 2-benzyloxyethyl methacrylate,4-chlorophenoxyethyl acrylate, 4-chlorophenoxyethyl methacrylate,2-phenoxyethoxyethyl acrylate, 2-phenoxyethoxyethyl methacrylate,N-phenyl acrylamide, N-phenyl methacrylamide, N-benzyl acrylamide,N-benzyl methacrylamide, N,N-dibenzyl acrylamide, N,N-dibenzylmethacrylamide, N-diphenylmethyl acrylamide, N-(4-methylphenyl)methylacrylamide, N-1-naphthyl acrylamide, N-4-nitrophenyl acrylamide,N-(2-phenylethyl)acrylamide, N-triphenylmethyl acrylamide,N-(4-hydroxyphenyl)acrylamide, N,N-methylphenyl acrylamide, N,N-phenylphenylethyl acrylamide, N-diphenylmethyl methacrylamide, N-(4-methylphenyl)methyl methacrylamide, N-1-naphthyl methacrylamide,N-4-nitrophenyl methacrylamide, N-(2-phenylethyl)methacrylamide,N-triphenylmethyl methacrylamide, N-(4-hydroxyphenyl)methacrylamide,N,N-methylphenyl methacrylamide, N,N′-phenyl phenylethyl methacrylamide,N-vinylcarbazole, 4-vinylpyridine, 2-vinylpyridine, styrene,2chlorostyrene, 3-chlorostyrene, 4-chlorostyrene, 2-bromostyrene,3-bromostyrene, 4-bromostyrene, 2,6-dichlorostyrene, 2-iodostyrene,3-iodostyrene, 4-iodostyrene, pentabromostyrene, 4-phenylstyrene,1-vinylnaphthalene, 2-vinylnaphthalene, 9-vinylanthracene and4-phenoxystyrene.

Preferred high refractive index monomers for use in the presentinvention include phenyl methacrylate, benzyl acrylate, benzylmethacrylate, 2-phenylethyl acrylate, 2-phenylethyl methacrylate,2-phenoxyethyl acrylate, 2-phenoxyethyl methacrylate, 2,3-dibromopropylacrylate, N-benzyl methacrylamide, N-vinylcarbazole, 2-phenylthioethylacrylate and 2-phenylthioethyl methacrylate to achieve the unexpectedlyhigh refractive index hydrogel materials of the present invention whichare both flexible and biocompatible.

The materials of the present invention are copolymers comprising a totalof at least approximately 70 but more preferably approximately 70 to 90but most preferably approximately 75 percent by weight of the twoprincipal components described above whereby the hydrophilic monomer ispresent in an amount greater than that of the high refractive indexmonomer to maximize water content.

Hydrogel compositions of the present invention include for example butare not limited to poly(2-hydroxyethyl methacrylate-co-phenyl acrylate),poly(2-hydroxyethyl methacrylate-co-phenyl methacrylate),poly(2-hydroxyethyl methacrylate-co-benzyl acrylate),poly(2-hydroxyethyl methacrylate-co-benzyl methacrylate),poly(2-hydroxyethyl methacrylate-co-2-phenylethyl acrylate),poly(2-hydroxyethyl methacrylate-co-2-phenylethyl methacrylate),poly(2-hydroxyethyl methacrylate-co-2-phenoxyethyl acrylate),poly(2-hydroxyethyl methacrylate-co-2henoxyethyl methacrylate),poly(2-hydroxyethyl methacrylate-co-phenylthioethyl acrylate),poly(2-hydroxyethyl methacrylate-co-phenylthioethyl methacrylate),poly(2-hydroxyethyl methacrylate-co-2,4,6-tribromophenyl acrylate),poly(2-hydroxyethyl methacrylate-co-2,4,6-tribromophenyl methacrylate),poly(2-hydroxyethyl methacrylate-co-pentabromophenyl acrylate),poly(2-hydroxyethyl methacrylate-co-pentabromophenyl methacrylate),poly(2-hydroxyethyl methacrylate-co-pentachlorophenyl acrylate),poly(2-hydroxyethyl methacrylate-co-pentachlorophenyl methacrylate),poly(2-hydroxyethyl methacrylate-co-2,3-dibromopropyl acrylate),poly(2-hydroxyethyl methacrylate-co-2,3-dibromopropyl methacrylate),poly(2-hydroxyethyl methacrylate-co-2-naphthyl acrylate),poly(2-hydroxyethyl methacrylate-co-2-naphthyl methacrylate),poly(2-hydroxyethyl methacrylate-co-4-methoxybenzyl acrylate),poly(2-hydroxyethyl methacrylate-co-4-methoxybenzyl methacrylate),poly(2-hydroxyethyl methacrylate-co-2-benzyloxyethyl acylate),poly(2-hydroxyethyl methacrylate-co-4-chlorophenoxyethyl acrylate),poly(2-hydroxyethyl methacrylate-co-2-phenoxyethoxyethyl acrylate),poly(2-hydroxyethyl methacrylate-co-2-benzyloxyethyl methacrylate),poly(2-hydroxyethyl methacrylate-co-4-chlorophenoxyethyl methacrylate),poly(2-hydroxyethyl methacrylate-co-2-phenoxyethoxyethyl methacrylate),poly(2-hydroxyethyl methacrylate-co-N-phenyl acrylamide),poly(2-hydroxyethyl methacrylate-co-N-phenyl methacrylamide),poly(2-hydroxyethyl methacrylate-co-N-benzyl acrylamide),poly(2-hydroxyethyl methacrylate-co-N-benzyl methacrylamide),poly(2-hydroxyethyl methacrylate-co-N,N-dibenzyl acrylamide),poly(2-hydroxyethyl methacrylate-co-N,N-dibenzyl methacrylamide),poly(2-hydroxyethyl methacrylate-co-N-diphenylmet acrylamide),poly(2-hydroxyethyl methacrylate-co-N-(4-methyl phenyl)methylacrylamide), poly(2-hydroxyethyl methacrylate-co-N-1-naphthylacrylamide), poly(2-hydroxyethyl methacrylate-co-N-4-nitrophenylacrylamide), poly(2-hydroxyethyl methacrylate-co-2-phenylethylacrylamide), poly(2-hydroxyethyl methacrylate-co-N-triphenylmethylacrylamide), poly(2-hydroxyethyl methacrylate-co-N-(4-hydroxyphenyl)acrylamide), poly(2-hydroxyethyl methacrylate-co-N,N-methyl phenylacrylamide), poly(2-hydroxyethyl methacrylate-co-N,N-phenyl phenylethylacrylamide), poly(2-hydroxyethyl methacrylate-co-N-diphenylmethylmethacrylamide), poly(2-hydroxyethyl methacrylate-co-N-(4-methylphenyl)methyl methacrylamide), poly(2-hydroxyethylmethacrylate-co-N-1-naphthyl methacrylamide), poly(2-hydroxyethylmethacrylate-co-N-(4-nitrophenyl methacrylamide), poly(2-hydroxyethylmethacrylate-co-2-phenylethyl methacrylamide), poly(2-hydroxyethylmethacrylate-co-N-triphenylmethyl methacrylamide), poly(2-hydroxyethylmethacrylate-co-N-(4-hydroxyphenyl) methacrylamide), poly(2-hydroxyethylmethacrylate-co-N,N-methyl phenyl methacrylamide), poly(2-hydroxyethylmethacrylate-co-N,N-phenyl phenylethyl methacrylamide),poly(2-hydroxyethyl methacrylate-co-N-vinylcarbazole),poly(2-hydroxyethyl methacrylate-co-4-vinylpyridine),poly(2-hydroxyethyl methacrylate-co-2-vinylpyridine),poly(2-hydroxyethyl methacrylate-co-styrene), poly(2-hydroxyethylmethacrylate-co-2-chlorostyrene), poly(2-hydroxyethylmethacrylate-co-3-chlorostyrene), poly(2-hydroxyethylmethacrylate-co-4-chlorostyrene), poly(2-hydroxyethylmethacrylate-co-2-bromostyrene), poly(2-hydroxyethylmethacrylate-co-3-bromostyrene), poly(2-hydroxyethylmethacrylate-co-4-bromostyrene), poly(2-hydroxyethylmethacrylate-co-2,6-dichlorostyrene), poly(2-hydroxyethylmethacrylate-co-2-iodostyrene), poly(2-hydroxyethylmethacrylate-co-3-iodostyrene), poly(2-hydroxyethylmethacrylate-co-4-iodostyrene), poly(2-hydroxyethylmethacrylate-co-pentabromostyrene), poly(2-hydroxyethylmethacrylate-co-4-phenylstyrene), poly(2-hydroxyethylmethacrylate-co-1-vinylnaphthalene), poly(2-hydroxyethylmethacrylate-co-2-vinyinaphthalene), poly(2-hydroxyethylmethacrylate-co-9-vinylanthracene), poly(2-hydroxyethylmethacrylate-co-4-phenoxystyrene), poly(hydroxyethoxyethylmethacrylate-co-phenyl methacrylate), poly(hydroxyethoxyethylmethacrylate-co-benzyl acrylate), poly(hydroxyethoxyethylmethacrylate-co-benzyl methacrylate), poly(hydroxyethoxyethylmethacrylate-co-2phenylethyl acrylate), poly(hydroxyethoxyethylmethacrylate-co-2-phenylethyl methacrylate), poly(hydroxyethoxyethylmethacrylate-co-2-phenoxyethyl acrylate), poly(hydroxyethoxyethylmethacrylate-co-2-phenoxyethyl methacrylate), poly(hydroxyethoxyethylmethacrylate-co-2,3-dibromopropyl acrylate), poly(hydroxyethoxyethylmethacrylate-co-N-benzyl methacrylamide), poly(hydroxyethoxyethylmethacrylate-co-N-vinylcarbazole), poly(hydroxyethoxyethylmethacrylate-co-2-phenylthioethyl methacrylate), poly(hydroxyethoxyethylmethacrylate-co-2-phenylthioethyl acrylate), poly(hydroxydiethoxyethylmethacrylate-co-phenyl methacrytate), poly(hydroxydiethoxyethylmethacrylate-co-benzyl acrylate), poly(hydroxydiethoxyethylmethacrylate-co-benzyl methacrylate), poly(hydroxydiethoxyethylmethacrylate-co-2-phenylethyl acrylate), poly(hydroxydiethoxyethylmethacrylate-co-2-phenylethyl methacrylate), poly(hydroxydiethoxyethylmethacrylate-co-2-phenoxyethyl acrylate), poly(hydroxydiethoxyethylmethacrylate-co-2-phenoxyethyl methacrylate), poly(hydroxydiethoxyethylmethacrylate-co-2,3-dibromopropyl acrylate), poly(hydroxydiethoxyethylmethacrylate-co-N-benzyl methacrylamide), poly(hydroxydiethoxyethylmethacrylate-co-N-vinylcarbazole), poly(hydroxydiethoxyethylmethacrylate-co-2-phenylthioethyl acrylate), poly(hydroxydiethoxyethylmethacrylate-co-phenylthioethyl methacrylate), poly(methoxyethylmethacrylate-co-phenyl methacrylate), poly(methoxyethylmethacrylate-co-benzyl acrylate), poly(methoxyethylmethacrylate-co-benzyl methacrylate), poly(methoxyethylmethacrylate-co-2-phenylethyl acrylate), poly(methoxyethylmethacrylate-co-2-phenylethyl methacrylate), poly(methoxyethylmethacrylate-co-2-phenoxyethyl acrylate), poly(methoxyethylmethacrylate-co-2-phenoxyethyl methacylate), poly(methoxyethylmethacrylate-co-2,3-dibromopropyl acrylate), poly(mothoxyethylmethacrylate-co-N-benzyl methacrylamide), poly(methoxyethylmethacrylate-co-N-vinyicarbazole), poly(methoxyethylmethacrylate-co-2-phenylthioethyl acrylate), poly(methoxyethylmethacrylate-co-2-phenylthioethyl methacrylate), poly(methoxyethoxyethylmethacryate-co-phenyl methacrylate), poly(methoxyethoxyethylmethacrylate-co-benzyl acrylate), poly(methoxyethoxyethylmethacrylate-co-benzyl methacrylate), poly(methoxyethoxyethyl,methacrylate-co-2-phenylethyl acrylate), poly(methoxyethoxyethylmethacrylate-co-2-phenylethyl methacrylate), poly(methoxyethoxyethylmethacrylate-co-2-phenoxyethyl acrylate), poly(methoxyethoxyethylmethacrylate-co-2-phenoxyethyl methacrylate), poly(methoxyethoxyethylmethacrylate-co-2,3-dibromopropyl acrylate), poly(methoxyethoxyethylmethacrylate-co-N-benzyl methacrylamide), poly(methoxyethoxyethylmethacrylate-co-N-vinylcarbazole), poly(methoxyethoxyethylmethacrylate-co-2-phenylthioethyl acrylate), poly(methoxyethoxyethylmethacrylate-co-2-phenylthioethyl methacrylate),poly(methoxydiethoxyethyl methacrylate-co-phenyl methacrylate),poly(methoxydiethoxyethyl methacrylate-co-benzyl acrylate),poly(methoxydiethoxyethyl methacrylate-co-benzyl methacrylate),poly(methoxydiethoxyethyl methacrylate-co-2-phenylethyl acrylate),poly(methoxydiethoxyethyl methacrylate-co-2-phenylethyl methacrylate),poly(methoxydiethoxyethyl methacrylate-co-2-phenoxyethyl acrylate),poly(methoxydiethoxyethyl methacylate-co-2-phenoxyethyl methacrylate),poly(methoxydiethoxyethyl methacrylate-co-2,3-dibromopropyl acrylate),poly(methoxydiethoxyethyl methacrylate-co-N-benzyl methacrylamide),poly(methoxydiethoxyethyl methacrylate-co-N-vinylcarbazole),poly(methoxydiethoxyethyl methacrylate-co-2-phenylthioethyl acrylate),poly(methoxydiethoxyethyl methacrylate-co-2-phenylthioethylmethacrylate), poly(poly(ethylene glycol)methacrylate-co-phenylmethacrylate), poly(poly(ethylene glycol)methacrylate-co-benzylacrylate), poly(poly(ethylene glycol)methacrylate-co-benzylmethacrylate), poly(poly(ethylene glycol)methacrylate-co-2-phenylethylacrylate), poly(poly(ethylene glycol)methacrylate-co-2-phenylethylmethacrylate), poly(poly(ethylene glycol)methacrylate-co-2-phenoxyethylacrylate), poly(poly(ethylene glycol)methacrylate-co-2-phenoxyethylmethacrylate), poly(poly(ethyleneglycol)methacrylate-co-2,3-dibromopropyl acrylate), poly(poly(ethyleneglycol)methacrylate-co-N-benzyl methacrylamide), poly(poly(ethyleneglycol)methacrylate-co-N-vinylcarbazole), poly(poly(ethyleneglycol)methacrylate-co-2-phenylthioethyl acrylate), poly(poly(ethyleneglycol)methacrylate-co-2-phenylthioethyl methacrylate),poly(methoxy-poly(ethylene glycol)methacrylate-co-phenyl methacrylate),poly(methoxy-poly(ethylene glycol)methacrylate-co-benzyl acrylate),poly(methoxy-poly(ethylene glycol)methacrylate-co-benzyl methacrylate),poly(methoxy-poly(ethylene glycol)methacrylate-co-2-phenylethylacrylate), poly(methoxy-poly(ethyleneglycol)methacrylate-co-2-phenylethyl methacrylate),poly(methoxy-poly(ethylene glycol)methacrylate-co-2-phenoxyethylacrylate), poly(methoxy-poly(ethyleneglycol)methacrylate-co-2-phenoxyethyl methacrylate),poly(methoxy-poly(ethylene glycol)methacrylate-co-2,3-dibromopropylacrylate), poly(methoxy-poly(ethylene glycol)methacrylate-co-N-benzylmethacrylamide), poly(methoxy-poly(ethyleneglycol)methacrylate-co-N-vinylcarbazole), poly(methoxy-poly(ethyleneglycol)methacrylate-co-2-phenylthioethyl acrylate),poly(methoxy-poly(ethylene glycol)methacrylate-co-2-phenylthioethylmethacrylate), poly(methacrylic acid-co-phenyl methacrylate),poly(methacrylic acid-co-benzyl acrylate), poly(methacrylicacid-co-benzyl methacrylate), poly(methacrylic acid-co-2-phenylethylacrylate), poly(methacrylic acid-co-2-phenylethyl methacrylate),poly(methacrylic acid-co-2-phenoxyethyl acrylate), poly(methacrylicacid-co-2-phenoxyethyl methacrylate), poly(methacrylicacid-co-2,3-dibromopropyl acrylate), poly(methacrylic acid-co-N-benzylmethacrylamide), poly(methacrylic acid-co-N-vinylcarbazole),poly(methacrylic acid-co-2-phenylthioethyl acrylate), poly(methacrylicacid-co-2-phenylthioethyl methacrylate), poly(sodiummethacrylate-co-phenyl methacrylate), poly(sodium methacrylate-co-benzylacrylate), poly(sodium methacrylate-co-benzyl methacrylate), poly(sodiummethacrylate-co-2-phenylethyl acrylate), poly(sodiummethacrylate-co-2-phenylethyi methacrylate), poly(sodiummethacrylate-co-2-phenoxyethyl acrylate), poly(sodiummethacrylate-co-2-phenoxyethyl methacrylate), poly(sodiummethacrylate-co-2,3-dibromopropyl acrylate), poly(sodiummethacrylate-co-N-benzyl methacrylamide), poly(sodiummethacrylate-co-N-vinylcarbazole), poly(sodiummethacrylate-co-2-phenylthioethyl acrylate), poly(sodiummethacrylate-co-2-phenylthioethyl methacrylate), poly(glycerolmethacrylate-co-phenyl methacrylate), poly(glycerolmethacrylate-co-benzyl acrylate), poly(glycerol methacrylate-co-benzylmethacrylate), poly(glycerol methacrylate-co-2-phenylethyl acrylate),poly(glycerol methacrylate-co-2-phenylethyl methacrylate), poly(glycerolmethacrylate-co-2phenoxyethyl acrylate), poly(glycerolmethacrylate-co-2-phenoxyethyl methacrylate), poly(glycerolmethacrylate-co-2,3-dibrormopropyl acaylate), poly(glycerolmethacrylate-co-N-benzyl methacrylamide), poly(glycerolmethacrylate-co-N-vinylcarbazole), poly(glycerolmethacrylate-co-2-phenylthioethyl acrylate), poly(glycerolmethacrylate-co-2-phenylthioethyl methacrylate), poly(hydroxypropylmethacrylate-co-phenyl methacrylate), poly(hydroxypropylmethacrylate-co-benzyl acrylate), poly(hydroxypropylmethacrylate-co-benzyl methacrylate), poly(hydroxypropylmethacrylate-co-2-phenylethyl acrylate), poly(hydroxypropylmethacrylate-co-2-phenylethyl methacrylate), poly(hydroxypropylmethacrylate-co-2-phenoxyethyl acrylate), poly(hydroxypropylmethacrylate-co-2-phenoxyethyl methacrylate), poly(hydroxypropylmethacrylate-co-2,3-dibromopropyl acrylate), poly(hydroxypropylmethacrylate-co-N-benzyl methacrylamide), poly(hydroxypropylmethacrylate-co-N-vinylcarbazole), poly(hydroxypropylmethacrylate-co-2-phenylithioethyl acrylate), poly(hydroxypropylmethacrylate-co-2-phenylthioethyl methacrylate), poly(hydroxybutylmethacrylate-co-phenyl methacrylate), poly(hydroxybutylmethacrylate-co-benzyl acrylate), poly(hydroxybutylmethacrylate-co-benzyl methacrylate), poly(hydroxybutylmethacrylate-co-2-phenylethyl acrylate), poly(hydroxybutylmethacrylate-co-2-phenylethyl methacrylate), poly(hydroxybutylmethacrylate-co-2-phenoxyethyl acrylate), poly(hydroxybutylmethacrylate-co-2-phenoxyethyl methacrylate), poly(hydroxybutylmethacrylate-co-2,3-dibromopropyl acrylate), poly(hydroxybutylmethacrylate-co-N-benzyl methacrylamide), poly(hydroxybutylmethacrylate-co-N-vinylcarbazole), poly(hydroxybutylmethacrylate-co-2-phenythioethyl acrylate) and poly(hydroxybutylmethacrylate-co-2-phenylthioethyl methacrylate).

Preferred hydrogel compositions of the present invention includepoly(2-hydroxyethyl methacrylate-co-phenyl methacrylate),poly(2-hydroxyethyl methacrylate-co-benzyl acrylate),poly(2-hydroxyethyl methacrylate-co-benzyl methacrylate),poly(2-hydroxyethyl methacrylate-co-2-phenylethyl acrylate),poly(2-hydroxyethyl methacrylate-co-2-phenylethyl methacrylate),poly(2-hydroxyethyl methacrylate-co-2-phenoxyethyl acrylate),poly(2-hydroxyethyl methacrylate-co-2-phenoxyethyl methacrylate),poly(2-hydroxyethyl methacrylate-co-N-benzyl methacrylamide) andpoly(2-hydroxyethyl methacrylate-co-N-vinylcarbazole) to achieve theunexpectedly high refractive index hydrogel materials of the presentinvention which are both flexible and biocompatible.

The subject hydrogel materials are synthesized by polymerizing one ormore of the above-described hydrophilic monomers with one or more highrefractive index monomers, most preferably having phenyl, sulfur orhalogen moieties, in the presence of at least 0.01 but more preferably0.01 to 2.0 mole percent crosslinker, at least 0.02 but more preferably0.02 to 2.0 weight percent initiator and optionally at least 0.1 butmore preferably 0.1 to 2.0 weight percent ultraviolet light absorber.

Suitable crosslinkers include for example but are not limited toethylene glycol dimethacrylate, diethylene glycol dimethacrylate,triethylene glycol dimethacrylate and poly(ethylene glycol)dimethacrylate wherein ethylene glycol dimethacrylate is preferred.Suitable initiators include for example but are not limited toazobis(isobutyronitrile), 2,2′-azobis(2,4-dimethylvaleronitrile),2,2′-azobis (methylbutyronitrile), 1,1′-azobis(cyanocyclohexane),di-t-butyl peroxide, dicumyl peroxide, t-butylcumyl peroxide,2,5dimethyl-2,5-bis(2ethylhexanoyl peroxy)hexane, t-butylperoxyneodecanote, t-butyl peroxy 2ethylhexanoate, di(4-t-butylcyclohexyl)peroxydicarbonate, t-butyl peroxypivalate, decanoyl peroxide,lauroyl peroxide, benzoyl peroxide, 2,4-pentanedione peroxide,di(n-propyl) peroxydicarbonate, t-amyl peroxyneodecanoate and t-butylperoxyacetate wherein 2,2′-azobis(isobutyronitrile) is preferred.Suitable ultraviolet light absorbers include for example but are notlimited to beta-(4-benzotriazoyl-3-hydroxyphenoxy) ethyl acrylate,4-(2-acyloxyethoxy)-2-hydroxybenzophenone,4-methacryloxy-2-hydroxybenzophenone,2-(2′-methacryloxy-5′-methylphenyl)benzotriazole,2-(2′-hydroxy-5′-methacryoxyethylphenyl)-2H-benzotriazole,2-[3′-tert-Butyl-2′-hydroxy-5′-(3″-methacryloyloxypropyl)phenyl]-5-chlorobenzotriazole,2-(3′-tert-Butyl-5′-(3″-dimethylvinylsilylpropoxy)-2′-hydroxyphenyl]-5-methoxybenzotriazole,2-(3′-Allyl-2′-hydroxy-5′-methylphenyl)benzotriazole,2-[3′-tert-Butyl-2′-hydroxy-5′-(3″methacryloyloxypropoxy)phenyl]-5-methoxybenzotriazole, and2-]3′-tert-Butyl-2′-hydroxy-5′-(3″-methacryloyloxypropoxy)phenyl]-5-chlorobenzotriazolewherein beta-(4-benzotriazoyl-3-hydroxyphenoxy)ethyl acrylate is thepreferred ultraviolet light absorber.

The subject hydrogel materials having a refractive index ofapproximately 1.45 or greater and approximately 5 to 30 percent water byweight measured by an Abbe refractometer at 589 nm and 37 degreesCelsius with a sodium light source are described in still greater detailin the examples that follow.

EXAMPLES Example 1 Monomers and Purification Thereof

HEMA of low acid, low inhibitor (LALI) grade was obtained from BenzResearch and Development, Sarasota, Fla. and was used without furtherpurification. Phenyl-containing acrylates and methacrylate were obtainedand purified as indicated below.

Monomer Source Purification 2-phenoxyethyl methacrylate Sartomer None(POEMA) West Chester, PA 2-phenylethyl methacrylate Polysciences None(PEMA) Warrington, PA 2-phenoxyethyl acrylate Polysciences Percolationthrough (POEA) Warrington, PA neutral alumina 2-phenylethyl acrylatePolysciences Percolation through (PEA) Warrington, PA basic alumina

Ethylene glycol dimethacrylate (EGDMA, Sartomer, West Chester, Pa.)crosslinker was extracted with aqueous NaOH and distilled from CuCl₂prior to use and azobis(isobutyronitrile) (AIBN) initiator was used asreceived from Polysciences.

Example 2 Polymer Synthesis

HEMA and each comonomer were combined in flasks in the following moleratios.

Mol HEMA/Mol Comonomer 90/10 85/15 80/20 75/25 70/30 65/35 60/40

Enough EGDMA crosslinker was added to comprise 0.25 mole percent oftotal moles of HEMA and comonomer. The amount of AIBN initiator added toeach solution was 0.05 to 0.1 weight percent of the total weight ofmonomers.

The unfiltered solutions were poured into polypropylene culture tubes(16×125 mm, Fisher Scientific), capped, and placed in a 60 degreeCelsius water bath for approximately 22 to 26 hours but most preferably24 hours. Post-cure was effected for approximately 22 to 26 hours butmost preferably 24 hours in a forced-air oven maintained at 120 degreesCelsius. The resultant polymer rods were demolded and sliced into 3.0 mmthick disks with a tool-room lathe. Five sample disks of eachcomposition were lathed to 2.0 mm thickness with a diamond-turninglathe.

Example 3 Polymer Characterizations

The initial masses of the disks prepared as described above weredetermined to 0.0001 g on an analytical balance. The disks were placedinto scintillation vials with 20 mL of balanced salt solution (BSS)Cytosol, Braintree, Mass., and hydrated in a constant temperature bathmaintained at 37 degrees Celsius, Lauda, Model RM 20, BrinkmannInstruments, Inc., Westbury, N.Y. The masses of the disks were checkedperiodically by blotting dry with a Kimwipe™, Kimberly-Clarke, Roswell,Ga., and weighing to 0.0001 g. After achieving constant mass, therefractive index of each specimen was determined on an Abbe™refractometer, Reichert-Jung, Model 10480, Reichert ScientificInstruments, Buffalo, N.Y., maintained at 37 degrees Celsius. Thesamples were then dried in a forced-air oven at 120 degrees Celsius forapproximately 18 to 30 hours, but more preferably 24 hours and reweighedto 0.0001 g.

The equilibrium water content (EWC) for each disk was determined usingthe following equation.${EWC},\quad {\% = {\frac{{{Mass}\quad ({hydrated})} - {{Mass}\quad ({dehydrated})}}{{Mass}\quad ({hydrated})} \times 100}}$

The average refractive index and standard deviation were calculated foreach composition. The Shore D hardness of non-hydrated HEMA/POEAcopolymer compositions was determined at room temperature with ahandheld durometer. The average hardness and standard deviation wasdetermined from ten measurements of each composition.

Example 4 Polymer Study Results

Three of the four groups of polymers had good optical clarity. HEMA/PEApolymers had a considerable amount of haze, yet the refractive indexcould be determined. HEMA/POEA and HEMA/PEA polymer series were flexibleand foldable at all formulations studied. Flexibility increased slightlywith increasing water content. HEMA/POEMA and HEMA/PEMA polymers wereflexible and foldable only in the cases of the highest water-containingcompositions.

All specimens were machined at room temperature. Harder specimens, i.e.,those with the highest HEMA content, were most easily lathe-cut. TheShore D hardness of the HEMA/POEA series of polymers demonstrated thatxerogel hardness decreased with increasing levels of POEA as set forthin Table 1 below. Both HEMA/methacrylate polymer series remained hardwith increasing methacrylate content.

TABLE 1 Shore D Hardness of HEMA/POEA Xerogel Compositions HEMA/POEAShore D Hardness +/− std. Dev. 90/10 84 +/= 2 85/15 83 +/− 1 80/20 83+/− 2 75/25 81 +/− 1 70/30 78 +/− 2 65/35 76 +/− 2 60/40 74 +/− 2

Equilibrium water content and refractive index results are presented inTables 2 and 3 below. For a given mass of HEMA and comonomer, themethacrylate monomers imparted higher hydrated refractive indexes thandid the acrylate monomers. The order of refractive index-enhancingeffectiveness of the phenyl monomer was as follows.

PEMA>POEMA>PEA>POEA

The refractive index of each composition was more dependent upon watercontent than phenyl-containing comonomer. However, per given mass ofHEMA and comonomer, the acrylic compositions contained more water thanthe methacrylate compositions. Accordingly, hydrogels with refractiveindexes above 1.5 are obtainable by copolymerizing HEMA withphenyl-containing acrylic monomers.

TABLE 2 Equilibrium Water Content (EWC) Results For HEMA CopolymersCOMONOMER Mole Ratio POEM PEM POEA PEA HEMA/comonomer EWC, % EWC, % EWC,% EWC, % (mol/mol) +/− std. dev. +/− std. dev. +/− std. dev. +/− std.dev. 90/10 22.42 +/− .01 22.75 +/− .04 24.43 +/− .05 24.79 +/− .01 85/1518.21 +/− .02 18.51 +/− .03 20.67 +/− .04 21.08 +/− .03 80/20 15.11 +/−.03 15.42 +/− .15 17.70 +/− .02 18.04 +/− .02 75/25 12.74 +/− .07 12.80+/− .09 15.19 +/− .06 15.55 +/− .02 70/30 10.90 +/− .21 10.63 +/− .1013.21 +/− .03 13.30 +/− .03 65/35  9.53 +/− .19  9.05 +/− .20 11.45 +/−.04 11.45 +/− .03 60/40  8.39 +/− .08  7.58 +/− .04  9.97 +/− .06  9.73+/− .02 Mole Ratio HEMA/comonomer DBPA* BA** BMA*** PMA**** BMAAM*****(mol/mol) EWC, % EWC, % EWC, % EWC, % EWC, % 95/5 30.0 29.1 28.8 28.831.5 90/10 22.5 24.9 23.0 23.1 27.8 85/15 19.8 21.0 18.7 18.4 23.8 80/2017.7 18.2 15.3 15.3 22.2 75/25 15.4 15.4 12.7 12.8 19.5 70/30 13.8 13.310.5 11.0 ND 65/35 11.3 ND ND ND ND 60/40 10.1 ND ND ND ND *DBPA =2,3-dibromopropyl acrylate **BA = benzyl acrylate ***BMA = benzylmethacrylate ****PMA = phenyl methacrylate *****BMAAM = benzylmethylacrylamide

TABLE 3 Refractive Index (RI) Results For HEMA Copolymers Mole RatioCOMONOMER HEMA/ POEM PEM POEA PEA comonomer RI RI RI RI (mol/mol) +/−std. dev. +/− std. dev. +/− std. dev. +/− std. dev. 90/10 1.4732 +/−1.4727 +/− 1.4676 +/− 1.4671 +/− .0003 .0003 .0003 .0001 85/15 1.4847+/− 1.4844 +/− 1.4771 +/− 1.4770 +/− .0002 .0001 .0002 .0004 80/201.4940 +/− 1.4941 +/− 1.4853 +/− 1.4853 +/− .0001 .0003 .0002 .000175/25 1.5021 +/− 1.5019 +/− 1.4927 +/− 1.4923 +/− .0004 .0004 .0003.0002 70/30 1.5094 +/− 1.5094 +/− 1.4990 +/− 1.4991 +/− .0009 .0006.0002 .0001 65/35 1.5152 +/− 1.5151 +/− 1.5049 +/− 1.5050 +/− .0010.0002 .0001 .0001 60/40 1.5204 +/− 1.5206 +/− 1.5104 +/− 1.5107 +/−.0002 .0002 .0002 .0003 Mole Ratio HEMA/comonomer DBPA BA BMA PMA BMAAM(mol/mol) RI RI RI RI RI 95/5  1.4594 1.4582 1.4593 1.4594 1.4526 90/101.4694 1.4685 1.4741 1.4737 1.4625 85/15 1.4760 1.4785 1.4858 1.48701.4727 80/20 1.4813 1.4862 1.4954 1.4971 1.4801 75/25 1.4856 1.49451.5041 1.5072 1.4891 70/30 1.4933 1.5020 1.5119 1.5125 ND

IOLs manufactured using the hydrogel materials of the present inventioncan be of any design capable of being rolled or folded into a smallcross section that can fit through a relatively small incision, i.e.,4.0 mm or less. For example, IOLs can be of a one-piece or multipiecedesign, and comprise optic and haptic portions. The optic portion isthat portion which serves as the lens and the haptic portions areattached to the optic portion to hold the optic portion in properalignment within an eye. The haptic portions may be integrally formedwith the optic portion in a one-piece design or attached by staking,adhesives or other methods known to those skilled in the art in amultipiece design.

The subject IOLs may be manufactured to have the optic portion and thehaptic portions made of the same or different materials. Preferably, inaccordance with the present invention, the optic portion and the hapticportions are made of the same high-refractive index hydrogel material.However, the optic portion and the haptic portions may also bemanufactured from different compositions and/or different formulationsof the same composition as described in detail in U.S. Pat. Nos.5,217,491 and 5,326,506, each incorporated herein in their entirety byreference. Once the particular hydrogel composition is selected, thematerial is cast in the form of rods and lathed into disks. These disksare then machined into IOLs. The IOLs are then cleaned, polished,packaged and sterilized by customary methods known to those skilled inthe art.

In addition to IOLs, the materials of the present invention are alsosuitable for use as other ophthalmic devices such as contact lenses,keratoprostheses, capsular bag extension rings, corneal inlays, cornealrings or like devices.

IOLs manufactured using the unique materials of the present inventionare used as customary in the field of ophthalmology. In a surgicalprocedure, an incision is placed in the corneal of an eye, most commonlythe natural lens of the eye is removed and the IOL manufactured frommaterials of the present invention is inserted into the posteriorchamber or lens capsule of the eye prior to closing the incision.

While there is shown and described herein certain specific structuresand compositions of the present invention, it will be manifest to thoseskilled in the art that various modifications may be made withoutdeparting from the spirit and scope of the underlying inventive conceptand that the same is not limited to particular structures herein shownand described except insofar as indicated by the scope of the appendedclaims.

I claim:
 1. A medical device manufactured from a composition comprising:an aromatic high refractive index monomer; a non-ultraviolet lightabsorbing hydrophilic monomer present in said composition in an amountgreater than that of said high refractive index monomer; a crosslinker;and an initiator to form a hydrogel composition having a fully hydratedwater content of approximately 5 to 30 percent by weight and a fullyhydrated refractive index of approximately 1.45 or greater.
 2. Themedical device of claim 1 wherein said composition includes ahydrophobic ultraviolet light absorbing material selected from the groupconsisting of beta-(4-benzotriazoyl-3-hydroxyphenoxy)ethyl acrylate,4-(2-acryloxyethoxy)-2-hydroxybenzophenone,4-methacryloxy-2-hydroxybenzophenone,2-(2′-methacryloxy-5′-methylphenyl)benzotriazole,2-(2′-hydroxy-5′-methacryoxyethylphenyl)-2H-benzotriazole,2-[3′-tert-Butyl-2′-hydroxy-5′-(3″-methacyloyloxypropyl)phenyl]-5-chlorobenzotriazole,2-(3′-tert-Butyl-5′-(3-dimethylvinylsilylpropoxy)-2′-hydroxyphenyl]-5-methoxybenzothiazole,2-(3′-Allyl-2′-hydroxy-5′-methylphenyl)benzotriazole,2-[3′-tert-Butyl-2′-hydroxy-5′-(3″-methacryloyloxypropoxy)]phenyl]-5-methoxybenzotriazoleand2-[3′-tert-Butyl-2′-hydroxy-5′-(3″-methacryloyloxypropoxy)phenyl]-5-chlorobenzotriazole.3. The medical device of claim 1 wherein said composition includesbeta-(4-benzotriazoyl-3-hydroxyphenoxy)-ethyl acrylate as an ultravioletlight absorbing material.
 4. The medical device of claim 1 wherein saidinitiator is selected from the group consisting ofazobis(isobutyronitrile), 2,2′-azobis(2,4-dimethylvaleronitrile),2,2′azobis(methylbutyronitrile), 1,1′-azobis(cyanocyclohexane),di-t-butyl peroxide, dicumyl peroxide, t-butylcumyl peroxide,2,5-dimethyl-2,5-bis(2-ethylhexanoylperoxy)hexane,t-butylperoxyneodecanote, t-butyl peroxy 2-ethylhexanoate, d i(4-t-butylcyclohexyl) peroxydicarbonate, t-butyl peroxypivalate, decanoylperoxide, lauroyl peroxide, benzoyl peroxide, 2,4-pentanedione peroxide,di(n-propyl)peroxydicarbonate, t-amyl peroxyneodecanoate and t-butylperoxyacetate.
 5. The medical device of claim 1 wherein said initiatoris azobis(isobutyronitrile).
 6. The medical device of claim 1 whereinsaid crosslinker is selected from the group consisting of ethyleneglycol dimethacrylate, diethylene glycol dimethacrylate, triethyleneglycol dimethacrylate and poly(ethylene glycol) dimethacrylate.
 7. Themedical device of claim 1 wherein said crosslinker is ethylene glycoldimethacrylate.
 8. The medical device of claim 1 wherein saidhydrophilic monomer is a monomer represented by the formula

wherein R₁ is selected from the group consisting of hydrogen and C₁₋₆alkyl, and R₂ is selected from the group consisting of hydrogen, analkali metal, an alkaline earth metal, C₁₋₆ hydroxyalkyl, C₄₋₁₂hydroxyalkoxyalkyl, C₄₋₁₂ hydroxydialkoxyalkyl, C₂₋₁₂ alkoxyalkyl, C₃₋₁₂polyalkoxyalkyl, C₃₋₁₅ polyalkoxyhydroxyalkyl and C₂₋₁₂ dihydroxyalkyl.9. The medical device of claim 1 wherein said hydrophilic monomer isselected from the group consisting of 2-hydroxyethyl methacrylate,hydroxyethoxyethyl methacrylate, hydroxydiethoxyethyl methacrylate,methoxyethyl methacrylate, methoxyethoxyethyl methacrylate,methoxydiethoxyethyl methacrylate, poly(ethylene glycol) methacrylate,methoxy-poly(ethylene glycol) methacrylate, methacrylic acid, sodiummethacrylate, glycerol methacrylate, hydroxypropyl methacrylate, andhydroxybutyl methacrylate.
 10. The medical device of claim 1 whereinsaid hydrophilic monomer is 2-hydroxyethyl methacrylate.
 11. The medicaldevice of claim 1 wherein said high refractive index monomer is amonomer represented by one of the formulas

wherein R₃ is selected from the group consisting of hydrogen and C₁₋₆alkyl, R₄ is selected from the group consisting of C₆₋₂₅ aryl, C₆₋₂₅hydroxyaryl, C₆₋₂₅ aryloxyaryl, C₁₂₋₂₅ polyhydroxyaryl, C₁₂₋₃₅ polyaryl,C₆₋₁₅ arylalkyl, C₁₂₋₃₅ polyarylalkyl, C₆₋₁₅ alkoxyaryl, C₆₋₁₅ arylhalides, C₆₋₁₅ aryloxyalkyl, C₁₋₇ alkyl halides, C₆₋₁₅ arylthioalkyl,C₆₋₁₅ aryloxyalkyl halides and C₆₋₁₅ aryloxyalkoxyalkyl, and R₅ isselected from the group consisting of hydrogen, C₁₋₃ alkyl and C₆₋₁₅alkylaryl.
 12. The medical device of claim 1 wherein said highrefractive index monomer is selected from the group consisting of phenylacrylate, phenyl methacrylate, benzyl acrylate, benzyl methacrylate,2-phenylethyl acrylate, 2-phenylethyl methacrylate, 2-phenoxyethylacrylate, 2-phenoxyethyl methacrylate, phenylthioethyl acrylate,phenylthioethyl methacrylate, 2,4,6-tribromophenyl acrylate,2,4,6-tribromophenyl methacrylate, pentabromophenyl acrylate,pentabromophenyl methacrylate, pentachlorophenyl acrylate,pentachlorophenyl methacrylate, 2,3-dibromopropyl acrylate,2,3-dibromopropyl methacrylate, 2-naphthyl acrylate, 2-naphthylmethacrylate, 4-methoxybenzyl acrylate, 4-methoxybenzyl methacrylate,2-benzyloxyethyl acrylate, 2-benzyloxyethyl methacrylate,4-chlorophenoxyethyl acrylate, 4-chlorophenoxyethyl methacrylate,2-phenoxyethoxyethyl acrylate, 2-phenoxyethoxyethyl methacrylate,N-phenyl acrylamide, N-phenyl methacrylamide, N-benzyl acrylamide,N-benzyl methacrylamide, N,N-dibenzyl acrylamide, N,N-dibenzylmethacrylamide, N-diphenylmethyl acrylamide N-(4-methylphenyl)methylacrylamide, N-1-naphthyl acrylamide, N-4-nitrophenyl acrylamide,N-(2-phenylethyl)acrylamide, N-triphenylmethyl acrylamide,N-(4-hydroxyphenyl)acrylamide, N,N-methylphenyl acrylamide, N,N-phenylphenylethyl acrylamide, N-diphenylmethyl methacrylamide, N-(4-methylphenyl)methyl methacrylamide, N-1-naphthyl methacrylamide,N-4-nitrophenyl methacrylamide, N-(2-phenylethyl)methacrylamide,N-triphenylmethyl methacrylamide, N-(4-hydroxyphenyl)methacrylamide,N,N-methylphenyl methacrylamide, N,N′-phenyl phenylethyl methacrylamide,N-vinylcarbazole, 4-vinylpyridine, 2-vinylpyridine, styrene,2-chlorostyrene, 3-chlorostyrene, 4-chlorostyrene, 2-bromostyrene,3-bromostyrene, 4-bromostyrene, 2,6-dichlorostyrene, 2-iodostyrene,3-lodostyrene, 4-iodostyrene, pentabromostyrene, 4-phenylstyrene,1-vinylnaphthalene, 2-vinylnaphthalene, 9-vinylanthracene and4-phenoxystyrene.
 13. The medical device of claim 1 wherein said highrefractive index monomer and said hydrophilic monomer comprise at leastabout 70 percent by weight of said composition.
 14. The medical deviceof claim 1 wherein said high refractive index monomer and saidhydrophilic monomer comprise approximately 75 percent by weight of saidcomposition.
 15. The medical device of claim 1 wherein said hydrophilicmonomer is 2-hydroxyethyl methacrylate and said high refractive indexmonomer is phenyl methacrylate.
 16. The medical device of claim 1wherein said hydrophilic monomer is 2-hydroxyethyl methacrylate and saidhigh refractive index monomer is benzyl acrylate.
 17. The medical deviceof claim 1 wherein said hydrophilic monomer is 2-hydroxyethylmethacrylate and said high refractive index monomer is benzylmethacrylate.
 18. The medical device of claim 1 wherein said hydrophilicmonomer is 2-hydroxyethyl methacrylate and said high refractive indexmonomer is 2-phenylethyl acrylate.
 19. The medical device of claim 1wherein said hydrophilic monomer is 2-hydroxyethyl methacrylate and saidhigh refractive index monomer is 2-phenylethyl methacrylate.
 20. Themedical device of claim 1 wherein said hydrophilic monomer is2-hydroxyethyl methacrylate and said high refractive index monomer is2-phenoxyethyl acrylate.
 21. The medical device of claim 1 wherein saidhydrophilic monomer is 2-hydroxyethyl methacrylate and said highrefractive index monomer is 2-phenoxyethyl methacrylate.
 22. The medicaldevice of claim 1 wherein said hydrophilic monomer is 2-hydroxyethylmethacrylate and said high refractive index monomer is N-benzylmethacrylamide.
 23. The medical device of claim 1 wherein saidhydrophilic monomer is 2-hydroxyethyl methacrylate and said highrefractive index monomer is N-vinylcarbazole.